1 /* 2 * OF helpers for the GPIO API 3 * 4 * Copyright (c) 2007-2008 MontaVista Software, Inc. 5 * 6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 */ 13 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/errno.h> 17 #include <linux/module.h> 18 #include <linux/io.h> 19 #include <linux/gpio/consumer.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_gpio.h> 23 #include <linux/pinctrl/pinctrl.h> 24 #include <linux/slab.h> 25 26 #include "gpiolib.h" 27 28 /* Private data structure for of_gpiochip_find_and_xlate */ 29 struct gg_data { 30 enum of_gpio_flags *flags; 31 struct of_phandle_args gpiospec; 32 33 struct gpio_desc *out_gpio; 34 }; 35 36 /* Private function for resolving node pointer to gpio_chip */ 37 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 38 { 39 struct gg_data *gg_data = data; 40 int ret; 41 42 if ((gc->of_node != gg_data->gpiospec.np) || 43 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 44 (!gc->of_xlate)) 45 return false; 46 47 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 48 if (ret < 0) 49 return false; 50 51 gg_data->out_gpio = gpiochip_get_desc(gc, ret); 52 return true; 53 } 54 55 /** 56 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 57 * @np: device node to get GPIO from 58 * @propname: property name containing gpio specifier(s) 59 * @index: index of the GPIO 60 * @flags: a flags pointer to fill in 61 * 62 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 63 * value on the error condition. If @flags is not NULL the function also fills 64 * in flags for the GPIO. 65 */ 66 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 67 const char *propname, int index, enum of_gpio_flags *flags) 68 { 69 /* Return -EPROBE_DEFER to support probe() functions to be called 70 * later when the GPIO actually becomes available 71 */ 72 struct gg_data gg_data = { 73 .flags = flags, 74 .out_gpio = ERR_PTR(-EPROBE_DEFER) 75 }; 76 int ret; 77 78 /* .of_xlate might decide to not fill in the flags, so clear it. */ 79 if (flags) 80 *flags = 0; 81 82 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 83 &gg_data.gpiospec); 84 if (ret) { 85 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 86 __func__, propname, np->full_name, index); 87 return ERR_PTR(ret); 88 } 89 90 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 91 92 of_node_put(gg_data.gpiospec.np); 93 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 94 __func__, propname, np->full_name, index, 95 PTR_ERR_OR_ZERO(gg_data.out_gpio)); 96 return gg_data.out_gpio; 97 } 98 99 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 100 int index, enum of_gpio_flags *flags) 101 { 102 struct gpio_desc *desc; 103 104 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 105 106 if (IS_ERR(desc)) 107 return PTR_ERR(desc); 108 else 109 return desc_to_gpio(desc); 110 } 111 EXPORT_SYMBOL(of_get_named_gpio_flags); 112 113 /** 114 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 115 * @gc: pointer to the gpio_chip structure 116 * @np: device node of the GPIO chip 117 * @gpio_spec: gpio specifier as found in the device tree 118 * @flags: a flags pointer to fill in 119 * 120 * This is simple translation function, suitable for the most 1:1 mapped 121 * gpio chips. This function performs only one sanity check: whether gpio 122 * is less than ngpios (that is specified in the gpio_chip). 123 */ 124 int of_gpio_simple_xlate(struct gpio_chip *gc, 125 const struct of_phandle_args *gpiospec, u32 *flags) 126 { 127 /* 128 * We're discouraging gpio_cells < 2, since that way you'll have to 129 * write your own xlate function (that will have to retrive the GPIO 130 * number and the flags from a single gpio cell -- this is possible, 131 * but not recommended). 132 */ 133 if (gc->of_gpio_n_cells < 2) { 134 WARN_ON(1); 135 return -EINVAL; 136 } 137 138 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 139 return -EINVAL; 140 141 if (gpiospec->args[0] >= gc->ngpio) 142 return -EINVAL; 143 144 if (flags) 145 *flags = gpiospec->args[1]; 146 147 return gpiospec->args[0]; 148 } 149 EXPORT_SYMBOL(of_gpio_simple_xlate); 150 151 /** 152 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 153 * @np: device node of the GPIO chip 154 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 155 * 156 * To use this function you should allocate and fill mm_gc with: 157 * 158 * 1) In the gpio_chip structure: 159 * - all the callbacks 160 * - of_gpio_n_cells 161 * - of_xlate callback (optional) 162 * 163 * 3) In the of_mm_gpio_chip structure: 164 * - save_regs callback (optional) 165 * 166 * If succeeded, this function will map bank's memory and will 167 * do all necessary work for you. Then you'll able to use .regs 168 * to manage GPIOs from the callbacks. 169 */ 170 int of_mm_gpiochip_add(struct device_node *np, 171 struct of_mm_gpio_chip *mm_gc) 172 { 173 int ret = -ENOMEM; 174 struct gpio_chip *gc = &mm_gc->gc; 175 176 gc->label = kstrdup(np->full_name, GFP_KERNEL); 177 if (!gc->label) 178 goto err0; 179 180 mm_gc->regs = of_iomap(np, 0); 181 if (!mm_gc->regs) 182 goto err1; 183 184 gc->base = -1; 185 186 if (mm_gc->save_regs) 187 mm_gc->save_regs(mm_gc); 188 189 mm_gc->gc.of_node = np; 190 191 ret = gpiochip_add(gc); 192 if (ret) 193 goto err2; 194 195 return 0; 196 err2: 197 iounmap(mm_gc->regs); 198 err1: 199 kfree(gc->label); 200 err0: 201 pr_err("%s: GPIO chip registration failed with status %d\n", 202 np->full_name, ret); 203 return ret; 204 } 205 EXPORT_SYMBOL(of_mm_gpiochip_add); 206 207 #ifdef CONFIG_PINCTRL 208 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 209 { 210 struct device_node *np = chip->of_node; 211 struct of_phandle_args pinspec; 212 struct pinctrl_dev *pctldev; 213 int index = 0, ret; 214 const char *name; 215 static const char group_names_propname[] = "gpio-ranges-group-names"; 216 struct property *group_names; 217 218 if (!np) 219 return; 220 221 group_names = of_find_property(np, group_names_propname, NULL); 222 223 for (;; index++) { 224 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 225 index, &pinspec); 226 if (ret) 227 break; 228 229 pctldev = of_pinctrl_get(pinspec.np); 230 if (!pctldev) 231 break; 232 233 if (pinspec.args[2]) { 234 if (group_names) { 235 ret = of_property_read_string_index(np, 236 group_names_propname, 237 index, &name); 238 if (strlen(name)) { 239 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 240 np->full_name); 241 break; 242 } 243 } 244 /* npins != 0: linear range */ 245 ret = gpiochip_add_pin_range(chip, 246 pinctrl_dev_get_devname(pctldev), 247 pinspec.args[0], 248 pinspec.args[1], 249 pinspec.args[2]); 250 if (ret) 251 break; 252 } else { 253 /* npins == 0: special range */ 254 if (pinspec.args[1]) { 255 pr_err("%s: Illegal gpio-range format.\n", 256 np->full_name); 257 break; 258 } 259 260 if (!group_names) { 261 pr_err("%s: GPIO group range requested but no %s property.\n", 262 np->full_name, group_names_propname); 263 break; 264 } 265 266 ret = of_property_read_string_index(np, 267 group_names_propname, 268 index, &name); 269 if (ret) 270 break; 271 272 if (!strlen(name)) { 273 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 274 np->full_name); 275 break; 276 } 277 278 ret = gpiochip_add_pingroup_range(chip, pctldev, 279 pinspec.args[0], name); 280 if (ret) 281 break; 282 } 283 } 284 } 285 286 #else 287 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 288 #endif 289 290 void of_gpiochip_add(struct gpio_chip *chip) 291 { 292 if ((!chip->of_node) && (chip->dev)) 293 chip->of_node = chip->dev->of_node; 294 295 if (!chip->of_node) 296 return; 297 298 if (!chip->of_xlate) { 299 chip->of_gpio_n_cells = 2; 300 chip->of_xlate = of_gpio_simple_xlate; 301 } 302 303 of_gpiochip_add_pin_range(chip); 304 of_node_get(chip->of_node); 305 } 306 307 void of_gpiochip_remove(struct gpio_chip *chip) 308 { 309 gpiochip_remove_pin_ranges(chip); 310 of_node_put(chip->of_node); 311 } 312